Reducing space heating demand from the residential building stock has been established as a crucial element of the energy transition across Europe. Focusing on Switzerland, this paper presents a bottom-up model (SwissRes) which allows to analyse the demand for space heating by building element and by building archetype (54 archetypes in total). The model is based on detailed data on the building envelope and heating systems of over 25,000 Cantonal Building Energy Performance Certificates (CECB PLUS). We identify three building characteristics which result in above-average final energy demand: rural typology (18% higher than urban), single-family houses (41% higher than multi-family) and in particular age of buildings (525% higher from newest to oldest). In combination, these three factors can lead to up to seven times higher demand per m2 and year in extreme cases compared to the most efficient archetype. Among buildings constructed before 1970, single-family houses (SFH) show very high specific final energy demand for space heating ranging between 170 and 200 kWh/m². On the national level, SFHs and multi-family houses (MFH) are featuring almost identical shares of total final energy demand. Buildings in suburban areas account for almost 50% of the total final energy demand. In total, the buildings constructed before 1980 account for 70% of the national final energy demand for space heating, with buildings constructed before 1920 contributing 22%. Most heat is lost through walls (40%) followed by windows (25%), roofs (17%) and the floor (18%). Losses from walls are particular high (73 kWh/m²) for buildings constructed between 1920 and 1945. Given the scalability of the model, it is readily applicable not only for the country as a whole but also for a province (canton), a city or a larger neighbourhood. The energy demand by archetype and building element identified with the SwissRes model can be used to assess the techno-economic potential of large-scale energy retrofit scenarios.